AVRs have a few quirks because the original ISA didn't consider parts with more than 8K program memory, so later some longer jumps where tacked on. A few instru

AVRs have a few quirks because the original ISA didn't consider parts with more than 8K program memory, so later some longer jumps where tacked on. A few instructions has a bunch of special cases for some common operations (eg. bit-based access to some, but not all, IO registers). It is kind-of-but-not-really orthogonal with comparatively many instructions for an 8 bit controller (about ~120). Not sure how it compares regarding "emulability".